A singular case of Graves' disease in congenital thyroid hemiagenesis

We report the observation of an unusual case of Graves' disease associated with thyroid hemiagenesis. A 41-year-old woman who presented with symptoms and clinical signs of hyperthyroidism was discovered to have thyroid hemiagenesia of the left lobe. Thyroid ultrasound scan showed enlargement of the right lobe with a single nodule, and absence of the left lobe; isotope scan showed homogeneous uptake in the single lobe and nodule. Ophthalmopathy, which was absent at presentation, developed after two years; after a further 2 years the patient developed decompensated hypothyroidism requiring thyroxine replacement. This is the first case of Graves' disease in thyroid hemiagenesis evolved to hypothyroidism, and a rare case of thyroid ophthalmopathy accompanying this condition.